How many more attempts before SpaceX gives up on first stage landing? They've tried twice for the barge and crashed both times, with a third attempt called off by rough waves. Three prior return tests without the barge also had mixed results. These experiments are bold and interesting, but they're not free.

How many more attempts before SpaceX gives up on first stage landing? They've tried twice for the barge and crashed both times, with a third attempt called off by rough waves. Three prior return tests without the barge also had mixed results. These experiments are bold and interesting, but they're not free.

I was watching the webcast in the office with some coworkers. A bit before liftoff, a couple of us were expressing high confidence it would work. Another guy said he was more skeptical. I offered him a bet with 10-1 odds, but he declined.

Now the question is what does this do for the customer prices and customer insurance premiums?

We presume the customer did not pay full launch price, but did they settle for a 30% cut?

At the end of the day if the end user price does not drop enough to expand the market (a lot) then SX could have gone on doing what they were doing and saved every cent spent on doing this. Which is the choice every previous ELV mfg has made.

Hopefully the price cut will be big enough to expand the market enough to make this effort worthwhile.

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BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Now the question is what does this do for the customer prices and customer insurance premiums?

We presume the customer did not pay full launch price, but did they settle for a 30% cut?

At the end of the day if the end user price does not drop enough to expand the market (a lot) then SX could have gone on doing what they were doing and saved every cent spent on doing this. Which is the choice every previous ELV mfg has made.

Hopefully the price cut will be big enough to expand the market enough to make this effort worthwhile.

No, because they could return to normal hours at Hawthorne production lines by making less S1 components.

But CommsX, if it goes, will lead to a big expansion in number of SpaceX launches.

Economics is off topic for this very narrowly focused thread. So is raw number of launches. I'm interested to see how low this percentage goes before it starts to climb again, though.

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"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

How many more attempts before SpaceX gives up on first stage landing? They've tried twice for the barge and crashed both times, with a third attempt called off by rough waves. Three prior return tests without the barge also had mixed results. These experiments are bold and interesting, but they're not free.

A recoverable stage is not an expendable stage with recovery hardware.

Of course he is is correct, really, but at the time I think everybody expected reusable stages would need far more obvious and integrated recovery hardware. The breakthrough with SpaceX is that they have utilised the MPS already on the stage and added the bare minimum of additional hardware. It's kind of obvious in hindsight, but it wasn't always so!

Of course he is is correct, really, but at the time I think everybody expected reusable stages would need far more obvious and integrated recovery hardware. The breakthrough with SpaceX is that they have utilised the MPS already on the stage and added the bare minimum of additional hardware. It's kind of obvious in hindsight, but it wasn't always so!

Anyone aware of the mass tradeoff to do 2nd stage recovery would automatically be trying to minimize what hardware they added due to the 1:1 trade in payload mass.

Using the MPS was always the obvious solution, but the massive difference between fully loaded and returned stage weights meant either multiple engines or very deep throttling.

What wasn't obvious was engine control authority with a high aspect ratio structure was inadequate. It's taken the grid fins and their associated hydraulics to supply enough control authority to make reliable landings possible. BTW since I'm unaware of any previous concept for 1st stage reuse that used grid fins (and there were several touted in the 60's and IIRC the 70's as well) I'd conclude that no one really looked at the problem with enough detail to know they were needed, which suggests all of those proposals were (at best) wishful thinking.

A fact any competitor planning to land a full first (or probably second) stage ignores at their peril.

I suspect (but can't prove) that you can make a stage stiff enough that engine TVC could do the job, and you would not have the complexity of the grid fins and their control system to deal with. However I also suspect that you add a lot more structural weight to do so, unless you go short and wide IE the Bono SSTO concepts. Given you didn't want to add the grid fins to begin with staying with an active system limits the additional weight.

And of course the big landing legs.

« Last Edit: 03/31/2017 10:10 AM by john smith 19 »

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BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

The even bigger misprediction ever since F9 1.1 was that SpaceX should stop "wasting everyone's time and money" with their reusability experiments, and that customers will abandon them because they "can't ​just fly the same configuration".

Both NASA and commercial customers proved very supportive, and clearly the path of self-funding development from revenue of the same flights proved the right way to go.

EDITAs for the title of the thread, bring tongue in cheek, SpaceX has a record of nailing all the hard things on the first try, and only failing later...

The good thing here is, once a life expectancy of the booster is determined for the number of reflights, the last flight can be an expendable launch, with a relatively low value payload.

For some things, like tires, there's something that is integral to that thing that gets used up, and when it's used up, you can't use it any more. For other things, like cars, there are some parts that get used up, such as tires and brake pads, but then you replace those and continue using the car.

It sounds like you're considering first stages to be like tires, but I think they're like cars. Cars can keep going indefinitely as long as you replace the things that get used up or broken.

Musk said they're planning for 10 flights with no refurbishment and 100 with light refurbishment, and that they really could do 1,000. So I think Musk thinks of them more like cars and less like tires.

So, I don't think there will ever be a point at which SpaceX decides a given first stage can't be reused and might as well be thrown away because it has reached the end of its life. They might still do expendable launches just because it's the only way to get the performance a given payload needs, but not because the booster can't be used any more.

I had the same feelings. Maybe landing just won't work. The F1 was planned to be recovered and they never even tried. Step by step they improved and kept my hopes up.

Even now, with such a success and history being made, there is no promise that they will get to fast relaunch.

If you look at that with a different question - "Are there laws of physics which say a RTLSed rocket can't possibly be fueled up and launched again in 24 hours?" - the answer is obvious. No such laws exist. Therefore, it can be done. Yes, it will need changes on the rocket and a lot of support machinery to make many operations automatic, but it can be done.

I'd say it can be cut down even to some ~4 hours.

An example where engineers simply had to cut down time to the absolute minimum - Formula 1 refuelings are below 10 seconds, tire changes are below 2 (!!!) seconds.

The good thing here is, once a life expectancy of the booster is determined for the number of reflights, the last flight can be an expendable launch, with a relatively low value payload.

For some things, like tires, there's something that is integral to that thing that gets used up, and when it's used up, you can't use it any more. For other things, like cars, there are some parts that get used up, such as tires and brake pads, but then you replace those and continue using the car.

It sounds like you're considering first stages to be like tires, but I think they're like cars. Cars can keep going indefinitely as long as you replace the things that get used up or broken.

Musk said they're planning for 10 flights with no refurbishment and 100 with light refurbishment, and that they really could do 1,000. So I think Musk thinks of them more like cars and less like tires.

So, I don't think there will ever be a point at which SpaceX decides a given first stage can't be reused and might as well be thrown away because it has reached the end of its life. They might still do expendable launches just because it's the only way to get the performance a given payload needs, but not because the booster can't be used any more.

I agree. Stages will continue to be used until something is found to be unsafe or uneconomical to refurbish, e.g. cracked welds on a tank dome etc. At that point any usable parts- engines, grid fins, avionics, etc- would be stripped off for reuse and the rest scrapped. This is how it works for other vehicles including aircraft.

So there will not be a point at which someone says 'this stage is safe to fly, but only once more'. Would you get on a plane where the technician had told you that??

The good thing here is, once a life expectancy of the booster is determined for the number of reflights, the last flight can be an expendable launch, with a relatively low value payload.

For some things, like tires, there's something that is integral to that thing that gets used up, and when it's used up, you can't use it any more. For other things, like cars, there are some parts that get used up, such as tires and brake pads, but then you replace those and continue using the car.

It sounds like you're considering first stages to be like tires, but I think they're like cars. Cars can keep going indefinitely as long as you replace the things that get used up or broken.

Musk said they're planning for 10 flights with no refurbishment and 100 with light refurbishment, and that they really could do 1,000. So I think Musk thinks of them more like cars and less like tires.

So, I don't think there will ever be a point at which SpaceX decides a given first stage can't be reused and might as well be thrown away because it has reached the end of its life. They might still do expendable launches just because it's the only way to get the performance a given payload needs, but not because the booster can't be used any more.

I agree. Stages will continue to be used until something is found to be unsafe or uneconomical to refurbish, e.g. cracked welds on a tank dome etc. At that point any usable parts- engines, grid fins, avionics, etc- would be stripped off for reuse and the rest scrapped. This is how it works for other vehicles including aircraft.

So there will not be a point at which someone says 'this stage is safe to fly, but only once more'. Would you get on a plane where the technician had told you that??

Plus what makes it acceptable to dump trash into the ocean once you get to that point.

I don't think we will see "safe to fly, but only one more time". (I agree with Kaputnik)

However I DO think we will see something like "this stage is a block 5, it's due for its 100 flight light overhaul in two flights, which costs X USD, but we really want to also upgrade it to a block 7[1] to be current, which costs 42X[2]... if we expend it, we can charge an FH price for customer S's 9 tonne[3] GTO mission, but do it with an F9 expendable, It's cheaper than the block 7 upgrade and we haven't shut down the Hawthorne line for the block 8 cutover, so we have enough stages in storage before the cutover... plus we don't put wear and tear on three FH cores, and save some propellant costs ... so let's expend it"

"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY